Ataxia-Telangiectasia is an inherited disease that affects both nervous and immune system. Cerebellum brain part abnormalities, that control coordination, lead to ataxia-uncoordinated movements. Such abnormal movements generally develop just when the children start to walk, but can be delayed until age four. Muscle weakness, slurred speech, and in some cases mental retardation also develop as a result.

Telangiectasia , in which eyes and skin capillaries are prominent, progresses between ages one and six generally most visible on arms, nose sides, ears and eyes. Sinus infections, bronchial infections, and pneumonia develop often and can cause chronic lungs problem. Endocrine system problems may cause diabetes, infertility, and small testes. Many children, who have Ataxia-Telangiectasia, develop cancers, particularly, stomach cancer, brain tumor, and leukemia.

Immune globulin infusions or injections , as well as antibiotics, help prevent infections, but do not cure the neurologic disorders. Ataxia-Telangiectasia usually progress to dementia, paralysis, to worsening weakness of muscles and such disease may be fatal.